Back-End Software Engineer Contractor

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London, Remote
The target locations for this position are London or remote in the UK. This is a short term temp position.

We are searching for the right engineer to join our team of engineers, generalists responsible for making sure the core dashboard for visualising our continuous integration is usable for engineers daily.

Treeherder processes the logs from builds and tests to see if there are failures and update the UI in near real time. It also allows engineers to visualize performance data to make sure that Firefox is responsive to our end users.

As a member of the Treeherder team you will be helping to maintain algorithms to try classify failure for test failures, performance regressions or build failures for engineers. Your work will help people decide whether we can ship Firefox or not.

As part of the open-source Mozilla project, you will publicly collaborate with our global employee and volunteer community to help ship a scalable web application and its different subsystems.

As a Web Engineer at Mozilla, you will…

  • Write open source JavaScript and Python focusing on clean and performant code
  • Crafting tools to improve engineer effectiveness on Treeherder
  • Maintain effective unit tests and documentation
  • Review team members code as well as get your code reviewed
  • Inspire and mentor community members to work on Treeherder with you
  • Make accurate estimates for upcoming work, communicate technical solutions effectively, and report progress
  • Work remotely or in one of our regional offices (list at
You should have...
  • Practical, hands-on experience building web sites or services
  • Passion for learning and experimenting
  • Pride in writing maintainable, pragmatic code
  • Knowledge of the fundamentals of web scalability

It would be nice if you have (or we can teach you if you don’t)..:

  • Understanding of Mercurial and Git.
  • Ability to work with a diverse, global community based in many different locations and timezones.
  • Experience writing and maintaining web applications.
  • Experience writing any of Python, Ruby, Groovy, Jython
  • Experience working with AngularJS, Angular or React
  • Experience working on NoSQL databases
About Mozilla

Mozilla exists to build the Internet as a public resource accessible to all because we believe that open and free is better than closed and controlled. Join us to work on the Web as the platform and help create more opportunity and innovation for everyone online.

We are an equal opportunity employer and value diversity at our company. We do not discriminate on the basis of race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status.